unordered_map::find

项目
06/09/2015

查找与指定键匹配的元素。

const_iterator find(const Key& keyval) const;

参数

keyval
搜索的键值。

备注

成员函数返回(keyval).first。unordered_map::equal_range

示例

// std_tr1__unordered_map__unordered_map_find.cpp 
// compile with: /EHsc 
#include <unordered_map> 
#include <iostream> 
 
typedef std::unordered_map<char, int> Mymap; 
int main() 
    { 
    Mymap c1; 
 
    c1.insert(Mymap::value_type('a', 1)); 
    c1.insert(Mymap::value_type('b', 2)); 
    c1.insert(Mymap::value_type('c', 3)); 
 
// display contents " [c 3] [b 2] [a 1]" 
    for (Mymap::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << it->first << ", " << it->second << "]"; 
    std::cout << std::endl; 
 
// try to find and fail 
    std::cout << "find('A') == " 
        << std::boolalpha << (c1.find('A') != c1.end()) << std::endl; 
 
// try to find and succeed 
    Mymap::iterator it = c1.find('b'); 
    std::cout << "find('b') == " 
        << std::boolalpha << (it != c1.end()) 
        << ": [" << it->first << ", " << it->second << "]" << std::endl; 
 
    return (0); 
    }